Muscle growth

Bodybuilders use three main strategies to maximize muscle hypertrophy:

• Strength training through weights or elastic/hydraulic resistance
• Specialized nutrition, incorporating extra protein^{[citation needed]} and supplements where necessary
• Adequate rest, including sleep and recuperation between workouts

Weight training

Weight training causes micro-tears to the muscles being trained; this is generally known as microtrauma. These micro-tears in the muscle contribute to the soreness felt after exercise, called delayed onset muscle soreness (DOMS). It is the repair to these micro-trauma that result in muscle growth^{[citation needed]}. Normally, this soreness becomes most apparent a day or two after a workout. However, as muscles become adapted to the exercises, soreness tends to decrease.^[8]

Weight training aims to build muscle by prompting two different types of hypertrophy: sarcoplasmic hypertrophy and myofibrillar hypertrophy. Sarcoplasmic hypertrophy leads to larger muscles and so is favored by bodybuilders more than myofibrillar hypertrophy which builds athletic strength. Sarcoplasmic hypertrophy is triggered by increasing repetitions, whereas Myofibrillar hypertrophy is triggered by lifting heavier weight.^[9] In either case, there is an increase in size and strength of the muscles (compared to if that same individual does not lift weights at all). However, the emphasis is different.

Many trainees like to cycle between the two methods in order to prevent the body from adapting (maintaining a progressive overload), possibly emphasizing whichever method more suits their goals. I.e, a bodybuilder will use sarcoplasmic hypertrophy most of the time, but may change to myofibrillar hypertrophy temporarily in order to move past a plateau.

Nutrition

The high levels of muscle growth and repair achieved by bodybuilders require a specialized diet. Generally speaking, bodybuilders require more calories than the average person of the same weight to provide the protein and energy requirements needed to support their training and increase muscle mass. A sub-maintenance level of food energy is combined with cardiovascular exercise to lose body fat in preparation for a contest. The ratios of food energy from carbohydrates, proteins, and fats vary depending on the goals of the bodybuilder.^[10]

Carbohydrates

Carbohydrates play an important role for bodybuilders. Carbohydrates give the body energy to deal with the rigors of training and recovery. Carbohydrates also promote secretion of insulin, a hormone enabling cells to get the glucose they need. Insulin also carries amino acids into cells and promotes protein synthesis.^{[citation needed]} Insulin has steroid-like effects in terms of muscle gains.^{[citation needed]} It is impossible to promote protein synthesis without the existence of insulin, and which means without carbohydrates, it is impossible to add muscle mass.^{[citation needed]} Bodybuilders seek out low-glycemic polysaccharides and other slowly digesting carbohydrates, which release energy in a more stable fashion than high-glycemic sugars and starches. This is important as high-glycemic carbohydrates cause a sharp insulin response, which places the body in a state where it is likely to store additional food energy as fat. However, bodybuilders frequently do ingest some quickly digesting sugars (often in form of pure dextrose or maltodextrin) after a workout. This may help to replenish glycogen stores within the muscle, and to stimulate muscle protein synthesis.^[11]

Protein

The motor proteins actin and myosin generate the forces exerted by contracting muscles. Current advice says that bodybuilders should consume 25-30% of protein per total calorie intake to further their goal of maintaining and improving their body composition.^[12] This is a widely debated topic, with many arguing that 1 gram of protein per pound of body weight per day is ideal, some suggesting that less is sufficient, while others recommending 1.5, 2, or more.^{[13][14][15][16]} It is believed that protein needs to be consumed frequently throughout the day, especially during/after a workout, and before sleep.^[17] There is also some debate concerning the best type of protein to take. Chicken, turkey, beef, pork, fish, eggs and dairy foods are high in protein, as are some nuts, seeds, beans and lentils. Casein or whey are often used to supplement the diet with additional protein. Whey protein is the type of protein contained in many popular brands of protein supplements, and is preferred by many bodybuilders because of its high Biological Value (BV) and quick absorption rates. Bodybuilders are usually thought to require protein with a higher BV than that of soy, which is additionally avoided due to its claimed estrogenic properties.^[18] Still, some nutrition experts believe that soy, flax seeds and many other plants that contain the weak estrogen-like compounds or phytoestrogens can be used beneficially, as phytoestrogens compete with estrogens for receptor sites in the male body and can block its actions. This can also include some inhibition of pituitary functions while stimulating the P450 system (the system that eliminates chemicals, hormones, drugs and metabolic waste product from the body) in the liver to more actively process and excrete excess estrogen.^[19][20] Cortisol decreases amino acid uptake by muscle, and inhibits protein synthesis.^[21]

Meals

Bodybuilders often split their food intake for the day into 5 to 7 meals of roughly equal nutritional content and attempt to eat at regular intervals (e.g. every 2 to 3 hours). This method can serve two purposes: to limit overindulging in the cutting phase, and to physically allow for the consumption of large volumes of food during the bulking phase. Contrary to popular belief, eating more frequently does not increase basal metabolic rate when compared to the traditional 3 meals a day. While food does have a metabolic cost to digest, absorb, and store, called the thermic effect of food, it depends on the quantity and type of food, not how the food is spread across the meals of the day. Well-controlled studies using whole-body calorimetry and doubly labeled water have demonstrated that there is no metabolic advantage to eating more frequently.^[22][23][24]

Dietary supplements

The important role of nutrition in building muscle and losing fat means bodybuilders may consume a wide variety of dietary supplements.^[25] Various products are used in an attempt to augment muscle size, increase the rate of fat loss, improve joint health, increase natural testosterone production, enhance training performance and prevent potential nutrient deficiencies.

Performance enhancing substances

Often bodybuilders use drugs such as anabolic steroids and precursor substances such as prohormones to increase muscle hypertrophy. Anabolic steroids cause muscle hypertrophy of both types (I and II) of muscle fibers caused likely by an increased synthesis of muscle proteins and are accompanied with undesired side effects including hepatotoxicity, gynecomastia, acne, male pattern baldness and a decline in the body's own testosterone production, which can cause testicular atrophy.^[26][27][28] Other performance enhancing substances used by competitive bodybuilders include human growth hormone (HGH), which can cause acromegaly.

Rest

Although muscle stimulation occurs in the gym lifting weights, muscle growth occurs afterward during rest. Without adequate rest and sleep, muscles do not have an opportunity to recover and build. About eight hours of sleep a night is desirable for the bodybuilder to be refreshed, although this varies from person to person.^[29] Additionally, many athletes find a daytime nap further increases their body's ability to build muscle. Some bodybuilders take several naps per day, during peak anabolic phases and during catabolic phases.^{[citation needed]}

Overtraining

Overtraining occurs when a bodybuilder has trained to the point where his workload exceeds his recovery capacity. There are many reasons that overtraining occurs, including lack of adequate nutrition, lack of recovery time between workouts, insufficient sleep, and training at a high intensity for too long (a lack of splitting apart workouts). Training at a high intensity too frequently also stimulates the central nervous system (CNS) and can result in a hyper-adrenergic state that interferes with sleep patterns.^[30] To avoid overtraining, intense frequent training must be met with at least an equal amount of purposeful recovery. Timely provision of carbohydrates, proteins, and various micronutrients such as vitamins, minerals, phytochemicals, even nutritional supplements are acutely critical.

It has been argued that overtraining can be beneficial. One article published by Muscle & Fitness magazine stated that you can "Overtrain for Big Gains". It suggested that if one is planning a restful holiday and they do not wish to inhibit their bodybuilding lifestyle too much, they should overtrain before taking the holiday, so the body can rest easily and recuperate and grow. Overtraining can be used advantageously, as when a bodybuilder is purposely overtrained for a brief period of time to super compensate during a regeneration phase.